Provided by: libprotocol-irc-perl_0.13-2_all 
NAME
"Protocol::IRC" - IRC protocol handling
DESCRIPTION
This mix-in class provides a base layer of IRC message handling logic. It allows reading of IRC messages
from a string buffer and dispatching them to handler methods on its instance.
Protocol::IRC::Client provides an extension to this logic that may be more convenient for IRC client
implementations. Much of the code provided here is still useful in client applications, so the reader
should be familiar with both modules.
MESSAGE HANDLING
Every incoming message causes a sequence of message handling to occur. First, the message is parsed, and
a hash of data about it is created; this is called the hints hash. The message and this hash are then
passed down a sequence of potential handlers.
Each handler indicates by return value, whether it considers the message to have been handled. Processing
of the message is not interrupted the first time a handler declares to have handled a message. Instead,
the hints hash is marked to say it has been handled. Later handlers can still inspect the message or its
hints, using this information to decide if they wish to take further action.
A message with a command of "COMMAND" will try handlers in following places:
1. A method called "on_message_COMMAND"
$irc->on_message_COMMAND( $message, \%hints )
2. A method called "on_message"
$irc->on_message( 'COMMAND', $message, \%hints )
For server numeric replies, if the numeric reply has a known name, it will be attempted first at its
known name, before falling back to the numeric if it was not handled. Unrecognised numerics will be
attempted only at their numeric value.
Because of the wide variety of messages in IRC involving various types of data the message handling
specific cases for certain types of message, including adding extra hints hash items, or invoking extra
message handler stages. These details are noted here.
Many of these messages create new events; called synthesized messages. These are messages created by the
"Protocol::IRC" object itself, to better represent some of the details derived from the primary ones from
the server. These events all take lower-case command names, rather than capitals, and will have a
"synthesized" key in the hints hash, set to a true value. These are dispatched and handled identically to
regular primary events, detailed above.
If any handler of the synthesized message returns true, then this marks the primary message handled as
well.
If a message is received that has a gating disposition, extra processing is applied to it before the
processing above. The effect on its gate is given as a string (one of "more", "done", "fail") to handlers
in the following places:
1. A method called "on_message_gate_EFFECT_GATE"
$irc->on_message_gate_EFFECT_GATE( $message, \%hints )
2. A method called "on_message_gate_EFFECT"
$irc->on_message_gate_EFFECT( 'GATE', $message, \%hints )
3. A method called "on_message_gate"
$irc->on_message_gate( 'EFFECT', 'GATE', $message, \%hints )
Message Hints
When messages arrive they are passed to the appropriate message handling method, which the implementation
may define. As well as the message, a hash of extra information derived from or relating to the message
is also given.
The following keys will be present in any message hint hash:
handled => BOOL
Initially false. Will be set to true the first time a handler returns a true value.
prefix_nick => STRING
prefix_user => STRING
prefix_host => STRING
Values split from the message prefix; see the "Protocol::IRC::Message" "prefix_split" method.
prefix_name => STRING
Usually the prefix nick, or the hostname in case the nick isn't defined (usually on server
messages).
prefix_is_me => BOOL
True if the nick mentioned in the prefix refers to this connection.
Added to this set, will be all the values returned by the message's "named_args" method. Some of these
values may cause yet more values to be generated.
If the message type defines a "target_name":
• target_type => STRING
Either "channel" or "user", as returned by "classify_name".
• target_is_me => BOOL
True if the target name is a user and refers to this connection.
Any key whose name ends in "_nick" or "_name" will have a corresponding key added with "_folded" suffixed
on its name, containing the value casefolded using "casefold_name". This is for the convenience of string
comparisons, hash keys, etc..
Any of these keys that are not the "prefix_name" will additionally have a corresponding key with "_is_me"
replacing the "_nick" or "_name", containing the boolean result of calling the "is_nick_me" method on
that name. This makes it simpler to detect commands or results affecting the user the connection
represents.
METHODS
on_read
$irc->on_read( $buffer )
Informs the protocol implementation that more bytes have been read from the peer. This method will modify
the $buffer directly, and remove from it the prefix of bytes it has consumed. Any bytes remaining should
be stored by the caller for next time.
Any messages found in the buffer will be passed, in sequence, to the "incoming_message" method.
incoming_message
$irc->incoming_message( $message )
Invoked by the "on_read" method for every incoming IRC message. This method implements the actual
dispatch into various handler methods as described in the "MESSAGE HANDLING" section above.
This method is exposed so that subclasses can override it, primarily to wrap extra logic before or after
the main dispatch (e.g. for logging or other processing).
send_message
This method takes arguments in three different forms, depending on their number and type.
If the first argument is a reference then it must contain a "Protocol::IRC::Message" instance which will
be sent directly:
$irc->send_message( $message )
Otherwise, the first argument must be a plain string that gives the command name. If the second argument
is a hash, it provides named arguments in a form similar to "new_from_named_args" in
Protocol::IRC::Message, otherwise the remaining arguments must be the prefix string and other positional
arguments, as plain strings:
$irc->send_message( $command, { %args } )
$irc->send_message( $command, $prefix, @args )
Named Argument Mangling
For symmetry with incoming message processing, this method applies some adjustment of named arguments for
convenience of callers.
• Callers may define a named argument of "target"; it will be renamed to "target_name".
• If a named argument of "text" is defined and an "encoder" exists, the argument value will be encoded
using this encoder.
send_ctcp
$irc->send_ctcp( $prefix, $target, $verb, $argstr )
Shortcut to sending a CTCP message. Sends a PRIVMSG to the given target, containing the given verb and
argument string.
send_ctcpreply
$irc->send_ctcpreply( $prefix, $target, $verb, $argstr )
Shortcut to sending a CTCP reply. As "send_ctcp" but using a NOTICE instead.
ISUPPORT-DRIVEN UTILITIES
The following methods are controlled by the server information given in the "ISUPPORT" settings. They use
the "isupport" required method to query the information required.
casefold_name
$name_folded = $irc->casefold_name( $name )
Returns the $name, folded in case according to the server's "CASEMAPPING" "ISUPPORT". Such a folded name
will compare using "eq" according to whether the server would consider it the same name.
Useful for use in hash keys or similar.
cmp_prefix_flags
$cmp = $irc->cmp_prefix_flags( $lhs, $rhs )
Compares two channel occupant prefix flags, and returns a signed integer to indicate which of them has
higher priviledge, according to the server's ISUPPORT declaration. Suitable for use in a "sort()"
function or similar.
cmp_prefix_modes
$cmp = $irc->cmp_prefix_modes( $lhs, $rhs )
Similar to "cmp_prefix_flags", but compares channel occupant "MODE" command flags.
prefix_mode2flag
$flag = $irc->prefix_mode2flag( $mode )
Converts a channel occupant "MODE" flag (such as "o") into a name prefix flag (such as "@").
prefix_flag2mode
$mode = $irc->prefix_flag2mode( $flag )
The inverse of "prefix_mode2flag".
classify_name
$classification = $irc->classify_name( $name )
Returns "channel" if the given name matches the pattern of names allowed for channels according to the
server's "CHANTYPES" "ISUPPORT". Returns "user" if not.
is_nick_me
$me = $irc->is_nick_me( $nick )
Returns true if the given nick refers to that in use by the connection.
INTERNAL MESSAGE HANDLING
The following messages are handled internally by "Protocol::IRC".
PING
"PING" messages are automatically replied to with "PONG".
NOTICE and PRIVMSG
Because "NOTICE" and "PRIVMSG" are so similar, they are handled together by synthesized events called
"text", "ctcp" and "ctcpreply". Depending on the contents of the text, and whether it was supplied in a
"PRIVMSG" or a "NOTICE", one of these three events will be created.
In all cases, the hints hash will contain a "is_notice" key being true or false, depending on whether the
original messages was a "NOTICE" or a "PRIVMSG", a "target_name" key containing the message target name,
a case-folded version of the name in a "target_name_folded" key, and a classification of the target type
in a "target_type" key.
For the "user" target type, it will contain a boolean in "target_is_me" to indicate if the target of the
message is the user represented by this connection.
For the "channel" target type, it will contain a "restriction" key containing the channel message
restriction, if present.
For normal "text" messages, it will contain a key "text" containing the actual message text.
For either CTCP message type, it will contain keys "ctcp_verb" and "ctcp_args" with the parsed message.
The "ctcp_verb" will contain the first space-separated token, and "ctcp_args" will be a string containing
the rest of the line, otherwise unmodified. This type of message is also subject to a special stage of
handler dispatch, involving the CTCP verb string. For messages with "VERB" as the verb, the following are
tried. "CTCP" may stand for either "ctcp" or "ctcpreply".
1. A method called "on_message_CTCP_VERB"
$irc->on_message_CTCP_VERB( $message, \%hints )
2. A method called "on_message_CTCP"
$irc->on_message_CTCP( 'VERB', $message, \%hintss )
3. A method called "on_message"
$irc->on_message( 'CTCP VERB', $message, \%hints )
REQUIRED METHODS
As this class is an abstract base class, a concrete implementation must provide the following methods to
complete it and make it useable.
write
$irc->write( $string )
Requests the byte string to be sent to the peer
encoder
$encoder = $irc->encoder
Optional. If supplied, returns an Encode object used to encode or decode the bytes appearing in a "text"
field of a message. If set, all text strings will be returned, and should be given, as Unicode strings.
They will be encoded or decoded using this object.
invoke
$result = $irc->invoke( $name, @args )
Optional. If provided, invokes the message handling routine called $name with the given arguments. A
default implementation is provided which simply attempts to invoke a method of the given name, or return
false if no method of that name exists.
If an implementation does override this method, care should be taken to ensure that methods are tested
for and invoked if present, in addition to any other work the method wishes to perform, as this is the
basis by which derived message handling works.
isupport
$value = $irc->isupport( $field )
Should return the value of the given "ISUPPORT" field.
As well as the all-capitals server-supplied fields, the following fields may be requested. Their names
are all lowercase and contain underscores, to distinguish them from server-supplied fields.
prefix_modes => STRING
The mode characters from "PREFIX" (e.g. "ohv")
prefix_flags => STRING
The flag characters from "PREFIX" (e.g. "@%+")
prefixflag_re => Regexp
A precompiled regexp that matches any of the prefix flags
prefix_map_m2f => HASH
A map from mode characters to flag characters
prefix_map_f2m => HASH
A map from flag characters to mode characters
chanmodes_list => ARRAY
A 4-element array containing the split portions of "CHANMODES";
[ $listmodes, $argmodes, $argsetmodes, $boolmodes ]
channame_re => Regexp
A precompiled regexp that matches any string beginning with a channel prefix character in
"CHANTYPES".
nick
$nick = $irc->nick
Should return the current nick in use by the connection.
nick_folded
$nick_folded = $irc->nick_folded
Optional. If supplied, should return the current nick as case-folded by the "casefold_name" method. If
not provided, this will be performed by case-folding the result from "nick".
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.36.0 2022-10-22 Protocol::IRC(3pm)